Animals: They were here first

The Value of a Sloth

As we know, sloths spend their entire existence just hanging out. They are the very epitome of laziness, or so we might assume. What is their raison d’être? And how did they come to have the name, ‘sloth’ in the first place?

After numerous hours deep in research, looking for answers to my questions about the humble sloth, I discovered a history that shows, yet again, the value of animals, and why we share this planet with them.

The story begins in 1514, when Gonzalo Fernandez de Oviedo y Valdes, better known as ‘Oviedo’ set sail for Panama under the good graces of King Ferdinand of Spain. Oviedo had long been dreaming of exploring the New World, in fact, he had befriended Christopher Columbus some years before, in hopes of tagging along on one of his explorations.

Oviedo’s father was secretary to the royal family and this proximity afforded Oviedo the opportunity to land a job at the age of thirteen as the aid to the Crown Prince Infante Juan. King Ferdinand and Queen Isabella had taken a liking to Oviedo, admiring his quick wit and affable ways. This early connection with royalty is what led Oviedo to gain an education and reputation as a gentleman and scholar into his adulthood. In recognition of his considerable writing skills, the King commissioned Oviedo to write up the history of the kings and queens of Spain. After accomplishing this work, Oviedo asked the King if he could be of some use on one of the explorations to the New World as a scribe of events. In 1514, the King appointed him as a veedor, an overseer of gold smelting in the new colonies. He also was given the assignment to document his impressions of the New World.

Oviedo’s book detailing his travels, “General and Natural History of the Indies”, published in 1535, became an instant best seller in Europe. Armchair travelers found themselves mesmerized by Oviedo’s drawings and descriptions of the exotic plants, animals, and people of Panama. One such animal depicted in his writings was the lowly sloth which Oviedo described with cursory disgust, “I have never seen an uglier or more useless creature.”

Oh, if only Oviedo were here today, he would surely change his opinion if he became aware of the scientific research that has recently revealed the tremendous value of sloths.

Here’s an excerpt from the Earth section of the BBC.com written by Henry Nicholls that will tell you all about it:

Sloths get bad press. In just about every language on the planet, the common name for these creatures has roughly the same meaning. The English have the “sloth” (one of the seven deadly sins). The French go for the “la paresse” (“the lazy one”). In German, it’s “das Faultier” (“lazy animal”). Spanish gives us “el perezoso” (“the lazy bear”). And so on.

There is, of course, some truth to this common view. But stereotypes tend to obscure a greater underlying truth.

Sloths are certainly slow (at absolute top whack they can travel at around 6 cm per second), but lazy they are not. Several years ago, I interviewed Rory Wilson, a biologist at Swansea University, in Wales, UK and the inventor of “the daily diary”, a nifty electronic gadget that records the movement of animals in incredible detail. At that time, the gizmo had mainly been used to study fast-moving creatures such as penguins and cormorants.

But Wilson was keen to use the device on slow creatures too and sloths were an obvious choice. The fact that they are slow doesn’t make them lazy, he tells me. “Nobody calls a bivalve lazy,” he says, talking about slow-moving shellfish such as mussels or clams. He has a point.In a world populated by predators like big cats and raptors, you’d think that swift would be good. The monkeys that inhabit the same forest canopy as the sloths of Central and South America have gone for this option. But sloths just laugh in the face of such danger, slowly closing their eyes as the simians scatter through the treetops. Instead of running for cover, sloths have opted for an even more impressive strategy: invisibility.

For a sloth, one of the most feared predators is the harpy eagle. “They are great big eagles with the most appallingly powerful talons and a wicked beak,” says Wilson. “A sloth just doesn’t have the slightest chance.” Unless, that is, it can move so slowly that the eagle can’t see it. “I suspect that sloths are not slothful at all, they are just bloody careful.”

Pulling off this trick requires incredible strength. Imagine a male gymnast performing on the rings, muscles quivering as he holds himself in a crucifix position then raises his legs to the horizontal position. For a sloth, such acrobatics is small potatoes. “It’ll just move into the sitting crucifix position completely serenely as if there’s no muscular effort involved at all, as if gravity is just turned off.”

Under Wilson’s supervision, doctoral student Becky Cliffe has been using the daily diary on the captive inmates at the world’s only sloth sanctuary in Costa Rica. When I called at the appointed time, she was unable to make it to the phone due to a sloth going into unexpected labour. It’s nice that a pregnant sloth has the capacity to surprise, I think.

When I eventually get through to Cliffe, I ask about the microbes that thrive in the sloth’s lush coat. Each one of the sloth’s hairs is basically folded in half. “The only benefit we can think of to the hair having that structure is so that algae can grow,” she says.

So the sloths want fur-dwelling friends, but why?

A recent study of the sloth’s fur revealed it is home to a range of fungi that are bioactive against strains of the parasites that cause malaria and Chagas disease, and against some human breast cancer cells. For the authors, the sloth’s fur was a novel environment for discovering interesting fungi with medical uses.

Sure, a gurning sloth looks like an idiot. But the truth about sloths is that humans have done a very bad job at figuring out why they do what they do. “There aren’t many mammals left on the planet that are so unusual yet we still know so little about,” says Cliffe.

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Here is a link to the white paper, “Sloth Hair as a Novel Source of Fungi with Potent Anti-Parasitic, Anti-Cancer and Anti-Bacterial Bioactivity”, published on January 15, 2014.

Here is a link to the story of Gonzalo Fernandez de Oviedo y Valdes, from the Mariner’s Museum.